Autoren Christoph Schmutz Daniela Schmuki Paolo Ambrosetti Marco Gaia Simon Rohling. 205 Aeronautical Climatological Information Lugano LSZA

Transcription

1 Autoren Christoph Schmutz Daniela Schmuki Paolo Ambrosetti Marco Gaia Simon Rohling 205 Aeronautical Climatological Information Lugano LSZA

2 Arbeitsbericht Nummer: 205 Autoren Christoph Schmutz Daniela Schmuki Paolo Ambrosetti Marco Gaia Simon Rohling Aeronautical Climatological Information Lugano LSZA und Herausgeber: MeteoSchweiz, 2004 Bestelladresse: Bundesamt für Meteorologie und Klimatologie (MeteoSchweiz) Office fédéral de météorologie et de climatologie (MétéoSuisse) Ufficio federale di meteorologia e climatologia (MeteoSvizzera) Uffizi federal per meteorologia e climatologia (MeteoSvizra) (MeteoSwiss) MeteoSchweiz Krähbühlstrasse 58 Postfach 514 CH-8044 Zürich Telefon Telefax info@meteoschweiz.ch

3 Table of Contents Aeronautical Climatological Information Lugano LSZA 1 Table of Contents Introduction 4 A Climatology 1. GEOGRAPHICAL SETTING 1.1. Overview Switzerland Overview Region Lugano 5 2. METEOROLOGICAL PATTERNS 2.1. Westerly Flow Synoptic Overview and Associated Weather Season of Encounter Local Weather Phenomena Aviation Hazards Northerly Flow Synoptic Overview and Associated Weather Season of Encounter Local Weather Phenomena Aviation Hazards Easterly Flow Synoptic Overview and Associated Weather Season of Encounter Local Weather Phenomena Aviation Hazards Southerly Flow Synoptic Overview and Associated Weather Season of Encounter Local Weather Phenomena Aviation Hazards Flat Pressure Pattern Synoptic Overview and Associated Weather Season of Encounter Local Weather Phenomena Aviation Hazards High Pressure Pattern Synoptic Overview and Associated Weather Season of Encounter Local Weather Phenomena Aviation Hazards 11 B Tables and Graphics 1. WIND 1.1. Wind Polygon Wind Polygon 10 Years Wind Polygon per Season Wind Polygon per Month Wind Polygon per Hour 17

4 Table of Contents Aeronautical Climatological Information Lugano LSZA Wind Speed and Direction Wind Speed and Direction 10 Years Wind Speed and Direction per Season Wind Speed and Direction per Month Wind Speed and Direction per Hour Cumulative Wind Speed and Direction Cumulative Wind Speed and Direction 10 Years Cumulative Wind Speed and Direction per Season Cumulative Wind Speed and Direction per Month Wind RWY 01 (19) Wind RWY 01 (19) 10 Years Wind RWY 01 (19) per Season Wind RWY 01 (19) per Month WIND GUSTS 2.1. Wind Gusts Wind Gusts 10 Years Maximum Wind Gust in 10 Years Wind Gusts per Season Wind Gusts per Month VISIBILITY AND CEILING 3.1. Visibility Hourly Visibility 10 Years Monthly Visibility 10 Years Hourly Visibility per Season Hourly Visibility per Month Ceiling Hourly Ceiling 10 Years Monthly Ceiling 10 Years Hourly Ceiling per Season Hourly Ceiling per Month Visibility and Ceiling Hourly Visibility and Ceiling 10 Years Monthly Visibility and Ceiling 10 Years Hourly Visibility and Ceiling per Season Hourly Visibility and Ceiling per Month TEMPERATURE 4.1. Temperature Temperature 10 Years Temperature per Month Maximum Temperature Maximum Temperature per Month Maximum Temperature in 10 Years Average Maximum Temperature Minimum Temperature Minimum Temperature per Month Minimum Temperature in 10 Years Average Minimum Temperature PRESSURE 5.1. Average Pressure (QNH) 75

5 Table of Contents Aeronautical Climatological Information Lugano LSZA Minimum Pressure (QNH) Minimum QNH per Month Minimum QNH in 10 Years Maximum Pressure (QNH) Maximum QNH per Month Maximum QNH in 10 Years WEATHER PHENOMENA 6.1. Freezing Rain Freezing Drizzle Snowfall Hail Snow Pellets Thunderstorm Fog (Without Shallow and Vicinity Fog) Shallow and Vicinity Fog Freezing Fog Rain Drizzle 80 Abbreviations 81

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7 Geographical Setting Aeronautical Climatological Information Lugano LSZA 5 A Climatology 1. GEOGRAPHICAL SETTING 1.1. Overview Switzerland N LFSB LSZH LSZR LSZG LSGC LSZB LSGG LSGS LSZA 27 NM / 50 km Figure 1: Most important airports of Switzerland 1.2. Overview Region Lugano Lugano airport (official elevation 915 ft / 279 m) is located 2.5 NM / 4 km west of Lugano City (see also figures 1 and 2). It is situated in the southern part of the Tessin, a region with low and moderate hills between the Alps and the plane of the Po river. The alpine foothills and behind them the Alps rise in the sector north-west to south-east of the airport. The orography of the hills next to the airport canalises the wind in two preferred directions: north and south. N Alps Pizzo di Vogorno Bellinzona Locarno Gridone Monte Stabbiello Monte Tamaro Lago di Como 2.5 NM / 4 km Monte Bre Lugano LSZA San Salvatore Lago di Lugano Monte Generoso Verbania Important Mountains in the Region: Pizzo di Vogorno 8012 ft / 2442 m Gridone 7179 ft / 2188 m Monte Stabbiello 6942 ft / 2116 m Monte Tamaro 6437 ft / 1962 m Monte Generoso 5581 ft / 1701 m Monte Bre 3035 ft / 925 m San Salvatore 2992 ft / 912 m Lago Maggiore Varese Chiasso Como Figure 2: 3 D map of the Lugano region Atlas of Switzerland Version 2

8 Meteorological Patterns Aeronautical Climatological Information Lugano LSZA 6 2. METEOROLOGICAL PATTERNS 2.1. Westerly Flow Synoptic Overview and Associated Weather Westerly flow is the dominant one among the four flow or advection patterns described here. This is true in respect of frequency and wind speed. The westerly flow pattern is typically associated with the frequent changes from warm to cold air masses and vice versa, which is connected to the passages of frontal zones. The activity depends on the wind speed, the humidity of the air mass and its stability, as well as the altitude and the structure of the mountain range, the air mass is flowing across. The eastern part of the northern alpine ridge is especially exposed to the changeability of this flow pattern. The south side of the Alps enjoys a certain protection during the whole year, the south-western part of Switzerland and the Valais only in summer time Season of Encounter This pattern may appear at any time of the year, but is more frequent during the winter season than in summer. The reason for this is the more frequent development of heavy depressions in the colder seasons due to an increase of the temperature difference between warm and cold air masses at the Polar Front. The weather in the southern part of the Alps is significantly less affected by the associated Westerlies than the northern part due to the barrier effect of the Alps. The absence of westerly flow near the ground protects the south from the typical gales that can affect the north Local Weather Phenomena Front Passes Over the Alps Fronts (particularly warm fronts) which accompany westerly flow are usually not very active in the southern part of the mountain ridge because of the barrier effect of the Alps. The weather near the main alpine ridge is dominated by dense clouds and some precipitation caused by the westerly winds. The rest of the region is only affected by some clouds at middle or high altitude with a small risk of precipitation. Nevertheless, a small change in the main wind direction in the upper troposphere from west to south-west has important consequences for the weather character south of the Alps (see also chapter 2.4 southerly flow). Freezing Rain The meteorological conditions for this weather phenomenon rarely occur in the southern part of the Alps. Indeed, freezing rain has never been observed in Lugano in the last 10 years. This extremely rare event happens when a warm front with a high freezing level slides over a rather deep cold air pool in the plane of the Po river. Snow Snowfall which reaches the lower part of the atmosphere (or even the ground) occurs in two situations: 1) A layer of cold air with temperatures near the freezing level is trapped near the ground. Even precipitation with light or moderate intensity falls as snow. 2) If the precipitation rate is intense enough and is falling through relative warm air near the ground, the warm layer is cooled down to a temperature near 0 C. Precipitation will then turn into snow after some hours - depending on the intensity. The visibility drops from m down to m or even below. In Lugano snowfall occurs from November to March but is mainly observed from December to February. Thunderstorm In summer, especially after a sunny period with high temperatures, the passage of cold air in the upper atmosphere can increase the instability of the air mass and thunderstorms are developed. They are usually active near the main ridge of the Alps. Sometimes the area of the airport is also affected, because thunderstorms can be advected from the Monte Rosa region. There is an increased chance for thunderstorms in the mountains and hills near the airport compared to other parts of the region Aviation Hazards Low ceiling and poor visibility within the frontal zones with onset of precipitation Turbulence and icing conditions in clouds Wind shear in frontal zones Gusts in passing cold fronts Snowfall (when temperatures are low enough) Rare cases of freezing rain, depending on the vertical temperature structure Post frontal weather conditions are very unsteady with gusts and rapid changes between good and bad conditions (north) Possibility of embedded CB`s in cold fronts (rarely in warm fronts) Alps and Jura obscured by clouds Crosswinds behind the cold fronts at Geneva airport (Joran wind)

9 Meteorological Patterns Aeronautical Climatological Information Lugano LSZA Northerly Flow Synoptic Overview and Associated Weather The northerly flow pattern combines air mass advection from the north-west and north. Typical for this situation is the marked difference in the type of weather between the western and eastern parts as well as between the northern and southern parts of Switzerland. On the continental and the regional scale the northern and the eastern areas of Europe are influenced by more cloudy and rainy weather (cyclonic character). The western and southern parts benefit from the influence of the following anticyclone, because these parts are further away from the dominating depression. In addition to that, the southern regions are favourably influenced by the leeward down draught (Foehn / Favonio) from the mountain range. Below 2000 m a flow split into north-east (Bise) in the west and into north-west in the east of the Swiss Plateau is observed Season of Encounter This pattern is more frequent in winter and spring, often occurs after a westerly flow and usually leads on the Swiss Plateau to a north-easterly flow regime (Bise). It normally lasts between 5 and 7 days, especially in summer and autumn periods of only 3 days are possible. Northerly flow is less frequent and of a shorter duration in the western than in the eastern part of Switzerland Local Weather Phenomena Barrier Clouds and Precipitation Due to the barrier effect of the Alps the northerly flow gets mainly blocked over the Swiss Plateau and foothills of the Alps, the pressure increases and the air mass rises over the Alps. A closed cloud layer occurs above the Swiss Plateau with the lowest ceiling close to the Alps, accompanied by precipitation along the northern mountain range and in eastern Switzerland. Nevertheless, clouds and precipitation can pass the Alps. In situations with northerly Foehn there is usually a gradient in the cloud coverage from north to south: Near the alpine ridge clouds can be very frequent and the sky is overcast with a ceiling between ft. Moving to the south the clouds dissipate and the ceiling rises. Precipitation is normally limited to the proximity of the alpine ridge unless the wind speed over the Alps is very high. Northerly Foehn The Foehn wind is caused by the pressure gradient between the northern (higher due to barrier effect) and southern part of the mountain range. The Alps disappear in clouds. In southern Switzerland severe clear air turbulence associated with terrain induced turbulence and low level wind gusts occur and the dry leeward down draught (Foehn wind) brings warm weather south of the Alps. The gustiness of the Foehn, which is called Favonio in Lugano, is significant. Gusts may reach 2 up to 4 times the mean velocity of the wind. The strongest wind gusts south of the Alps are usually observed in Foehn situations. Thunderstorm Situations with light Foehn in summer trigger a convergence line near the borders between Switzerland and Italy. Thunderstorms frequently develop along this convergence line Aviation Hazards North of the Alps: - Poor visibility, low ceiling ( ft / grd) and precipitation - Icing conditions in clouds - Mountains obscured by clouds - Heavy snowfall for several hours between November and April South of the Alps: - Severe turbulence over and south of the mountains - Low-level wind gusts - Mountains near the alpine ridge obscured by clouds

10 Meteorological Patterns Aeronautical Climatological Information Lugano LSZA Easterly Flow Synoptic Overview and Associated Weather The easterly flow pattern develops after a significant pressure gradient from north-east to south-west across the Alps has been built up. In Switzerland the type of weather connected with this situation has usually an anticyclonic influence. However, in cases of a northern position of an active Mediterranean depression, cyclonic influence is dominating. The plains on either side of the Alps may be under a cover of low stratus combined with a persistent inversion and dry, subsiding air above the low clouds (elevated fog or stratus). The continental easterly wind called Bise accelerates over the Swiss Plateau between the Jura and the Alps and achieves its maximum speed at the bottleneck of Geneva. However, Bise is not exclusively associated to an easterly flow weather type Season of Encounter This pattern is very frequent in winter and spring, rarely occurs in summer and can last for several days. It is less frequent than westerly, northerly or southerly flow. Because of the flow split the Bise is more frequent in the western part than in the eastern part of Switzerland Local Weather Phenomena Stratus In situations with a high pressure system moving from west to east relative cold air can pass over the rather low eastern Alps (Austria), descending in the Pianura Padana and then coming back to the western part of the Alps. The moderately moist air over the Pianura Padana is pushed to the southern slope of the Alps and generates stratus clouds with a ceiling between ft. During winter this stratus may last during the whole day. In summer it usually dissipates during the first hours of the morning. A persistent overcast sky rarely occurs; nevertheless stratus situations (with a diurnal cycle) can last for several days. Above the stratus layer the atmosphere is clear due to anticyclonic influence Aviation Hazards Strong winds and turbulence near the ground especially in western Switzerland Elevated fog: - Poor visibility below the stratus layer - Often closed cloud layer over the Swiss Plateau - Gaps in the cloud layer may close again quite rapidly Stratus: - Poor visibility below the stratus layer - Mountains obscured by cloud - Gaps in the cloud layer may close again quite rapidly

11 Meteorological Patterns Aeronautical Climatological Information Lugano LSZA Southerly Flow Synoptic Overview and Associated Weather Southerly flow patterns are considerably rarer than the northerly ones that also belong to the meridional flow types. The activity of the southerly flow pattern is sustained by a surface depression over the eastern North Atlantic and western Europe. The west to east direction of the Alps causes the development of Foehn winds on the leeward side combined with a strong pressure gradient from south to north. Foehn situations north of the Alps are often associated with southerly flow. The usually dry and rather sunny Foehn weather to the north of the alpine ridge is in striking contrast to the humid weather along the southerly slopes of the Alps. There is also a subtype of the Foehn situation which is restricted to the typical Foehn valleys within the Alps when the pressure gradient is not too accentuated. South-westerly flow (wind direction at 500 hpa less than 230 ) has a similar effect on the region south of the Alps Season of Encounter The southerly flow pattern is very frequent in autumn, less frequent in winter and spring, but sometimes occurs even in summer. Since Foehn winds may also develop in other synoptic situations like south easterly and westerly flow patterns or in a low pressure system, southerly Foehn winds are more frequent than just the southerly flow patterns Local Weather Phenomena Barrier Clouds and Precipitation With southerly flow the alpine ridge acts like a barrier. The humid air mass, which comes from the Mediterranean Sea, flows over the Alps. In this case the presence of an easterly low level jet over the plane of the Po river reinforces the convergence near the Alps. Humidity condenses to clouds and causes precipitation on the windward side. Precipitation can last for several days (sometimes even weeks) and may cause considerable amounts of precipitation during short time. The cloud cover can be very persistent with a low ceiling. Visibility near the ground is also poor (1500 to 300 m or even less, during periods with high precipitation intensity). Since fronts may be stationary and embedded thunderstorms can be developed over the region, large amounts of precipitation can be observed with this weather situation. Foehn Wind In the Foehn valleys at the northern side of the Alps it is mostly warm, windy and dry with high visibility. When the pressure gradient is big enough, the warm and dry Foehn influences the central and eastern part of Switzerland. Approaching fronts from the west usually are slowed down and the sky keeps relatively clear Aviation Hazards South of the Alps: - Very low ceiling, poor visibility, persistent and sometime heavy precipitation, icing conditions in clouds - Embedded thunderstorms with associated heavy turbulence in summer - Mountains obscured by clouds North of the Alps: - Lee waves, turbulence - Wind shear when the dry warm Foehn wind flows over the cold air pool of the Swiss Plateau or when the Foehn gets weak by the approaching front in the west - High temperatures reduce engine performance

12 Meteorological Patterns Aeronautical Climatological Information Lugano LSZA Flat Pressure Pattern Synoptic Overview and Associated Weather Flat Pressure Pattern with Thermal Thunderstorms Flat pressure leads to a weak or inexistent synoptic flow. In contrary to the anticyclonic regime there is only little or no subsidence, which leads to a high chance of convection. In the indifferent situation of this pattern the weather shows a distinct diurnal variation: after sunshine during the first half of the day, deep convection clouds are building up, but not exclusively in mountainous terrain. Thermal thunderstorms are induced. Winds aloft carry the upper sections of convective clouds away from the place of formation. Thunderstorms induced by these thermal and orographic conditions show an irregular pattern in the distribution of the total amount of precipitation. Great differences may be observed within a distance of only a few kilometres! Flat Pressure Pattern with Frontal Thunderstorms The continuous warming of the land mass in flat pressure situations increases the temperature difference between the continent and the adjacent sea surface. This creates a pressure gradient between the continent and the ocean. In summer this repeatedly leads to outbreaks of cool and moist maritime air masses towards the Alps. With reference to the similar but more pronounced situation in southern Asia, the above development has been named European Summer Monsoon. Thunderstorms which develop in the immediate vicinity of such an outbreak of cold air are called frontal thunderstorms. If the passage of the cold front happens to coincide with the time of greatest diurnal warming or just after, the activity of the frontal thunderstorms is again increased Season of Encounter Synoptic situation with a small horizontal surface pressure gradient over large parts of a continent are most frequent during the summer, since temperature differences between polar and tropical region are smallest in this particular season. This pattern usually lasts for several days Local Weather Phenomena Convection During hot days a lot of warm air bubbles are lifted and rise up to the condensation base, where they turn into cumulus clouds. Below the convection clouds moderate to severe turbulence with strong vertical winds occur. Cumulus congestus may rise quickly up to the tropopause. Typically cumulonimbus capillatus (CB) with anvil produce thunderstorms. As a rule-of-thumb, the difference between dew-point and temperature multiplied by 400 equals the cloud base height in feet. Thunderstorm Thermal thunderstorms occur due to convection from mid afternoon to late evening, while frontal thunderstorms happen at any time of the day. Very heavy thunderstorms are the result of a line of frontal thunderstorms which reach a convecting air mass during the late afternoon in summer. Thunderstorms are accompanied with different aviation hazard, such as heavy rain and fog with reduced visibility. Occasionally precipitation also falls in the form of hail which can damage the structure of an airplane. Wind shear, strong gusts and strong up and down draughts occur near the thunderstorm. In Lugano thunderstorms are most frequent from May to September between 12 and 00 UTC. High Temperatures This weather pattern is normally accompanied by very high temperatures in summer. The density of hot air decreases and this leads to a dangerous decrease of the engine performance, too Aviation Hazards Thunderstorm: - Heavy rain with reduced visibility and rapid cooling - Severe wind shear and gusts in proximity of thunderstorms - Sudden gusts up to 60 kt - Lightning - Hail in strong thunderstorms - Outflow of cold air associated with sudden change of the wind regime at distant places from the active thunderstorm - Microbursts (very strong and small scaled outflow of cold air usually associated with CB s) Visibility frequently reduced due to haze High temperatures reduce engine performance

13 Meteorological Patterns Aeronautical Climatological Information Lugano LSZA High Pressure Pattern Synoptic Overview and Associated Weather This pattern normally produces favourable conditions for the aviation because of the influence of an anticyclone with strong subsidence. That sinking process increases the temperature of the air masses due to compression. The relative humidity decreases and clouds dissolve. Warm anticyclones are accompanied by distinct flow patterns aloft. On continental scale this prevents cyclones and frontal zones to enter regions with anticyclones. High Pressure Pattern in Summer The atmospheric pressure is higher than the average values and only few convective clouds are produced. The convective clouds are mostly limited to mountainous regions. Over the Alps of Switzerland a thermal low can be observed. It is caused by the excessive heating of alpine air during the day in comparison with air over the plain at the same height. The daytime heating is clearly stronger on the valley bottom than at higher levels. In this season the Azores high can also expand up to central Europe and guarantees high temperatures and clear sky for several days or even weeks. High Pressure Pattern in the Colder Seasons From November to March maintained anticyclonic conditions repeatedly occur over the continent. After several days of subsidence a very strong temperature inversion is formed which is a few hundred meters thick. The negative radiation balance of the surface during the winter half year prevents the subsidence from reaching the lowest atmospheric layer Season of Encounter High Pressure Pattern is observed at any time of the year and can last between one day and several weeks. They usually last longer in summer and winter, because approaching strong Atlantic cyclones in spring and autumn degrade the ridge of the high pressure. In summer this pattern often degenerates to a flat pressure pattern with air mass thunderstorms Local Weather Phenomena Radiation Fog The important conditions for radiation fog are clear sky (increased radiation with the development of an inversion layer), low wind speed and high relative humidity. South of the Alps these conditions are usually fulfilled during the first night with clear sky after a period of precipitation. The formation of radiation fog, which is not connected to a precipitation event, is rarely observed in the region of the airport Lugano. It may occur when radiation fog from plane of the Po river, where this phenomenon is frequently observed, moves toward the Alps caused by a small pressure gradient. This fog rises into the valleys on the southern part of the mountains. The visibility in areas with radiation fog can drop quite rapidly from m to m. In Lugano radiation fog is observed during the whole year, but mainly occurs from October to April. Fog doesn t usually last for the whole day but concentrates on the morning and evening hours. Even in winter, there is a high chance for fog dissipation during the late morning or afternoon hours. High Temperatures This weather pattern is normally accompanied by very high temperatures in summer. The density of hot air decreases and this leads to a dangerous decrease of the engine performance, too Aviation Hazards High temperatures reduce engine performance Haze reduces visibility in summer Isolated thunderstorms in summer when the anticyclone weakens by surface heating Radiation fog, fog patches and mist decrease visibility in autumn and winter Radiation fog can occur quite quickly and decrease visibility to m

14 Wind Aeronautical Climatological Information Lugano LSZA 12 B Tables and Graphics 1. WIND 1.1. Wind Polygon Wind Polygon 10 Years Frequencies in percent of occurrence of concurrent wind direction every 10 and wind speed within specified ranges (legend). Frequencies are calculated relative to all potentially possible minus the not available (NA) observations. The value of NA is calculated relative to the potentially possible observations. It indicates the reduction of the data base due to NA. Calm is for the wind speed with 0 kt. Variable is for the wind speed between 1 and 3 kt and no wind direction. Example: In the 10 years period 9.4 % of all observations showed a wind speed between 1 and 15 knots with a concurrent wind direction of 190 degrees. 10 Years > 40 kt kt kt kt 6-10 kt kt NA: 37.5 % Calm: 51.1 % Variable: 1.3 %

15 Wind Aeronautical Climatological Information Lugano LSZA Wind Polygon per Season Example: In the 10 years period in winter 4.2% of all observations showed a wind speed between 1 and 25 knots with a concurrent wind direction of 200 degrees. Winter (Dec/Jan/Feb) Spring (Mar/Apr/May) > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 43.5 % NA: 35.6 % Calm: 67.6 % Calm: 40.0 % Variable: 0.8 % Variable: 1.3 % Summer (Jun/Jul/Aug) Autumn (Sep/Oct/Nov) > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 35.7 % NA: 35.1 % Calm: 37.9 % Calm: 61.1 % Variable: 2.1 % Variable: 1.1 %

16 Wind Aeronautical Climatological Information Lugano LSZA Wind Polygon per Month Example: In the 10 years period in January 4.1% of all observations showed a wind speed between 1 and 25 knots with a concurrent wind direction of 360 degrees. January February > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 44.6 % NA: 48.0 % Calm: 72.3 % Calm: 54.1 % Variable: 0.6 % Variable: 1.0 % March April > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 35.6 % NA: 36.4 % Calm: 40.2 % Calm: 37.3 % Variable: 0.9 % Variable: 1.8 %

17 Wind Aeronautical Climatological Information Lugano LSZA 15 May June > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 34.9 % NA: 34.8 % Calm: 42.5 % Calm: 35.9 % Variable: 1.3 % Variable: 2.4 % July > 40 kt kt kt kt 6-10 kt 1-5 kt August > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 37.2 % NA: 35.1 % Calm: 36.1 % Calm: 41.6 % Variable: 2.2 % Variable: 1.6 %

18 Wind Aeronautical Climatological Information Lugano LSZA 16 September October > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 35.0 % NA: 34.9 % Calm: 51.5 % Calm: 64.7 % Variable: 1.8 % Variable: 0.6 % November December > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 35.3 % NA: 38.4 % Calm: 67.1 % Calm: 73.8 % Variable: 1.0 % Variable: 0.8 %

19 Wind Aeronautical Climatological Information Lugano LSZA Wind Polygon per Hour Example: In the 10 years period between 03 and 04 UTC 5.3% of all observations showed a wind speed between 1 and 25 knots with a concurrent wind direction of 360 degrees. Attention must be paid to the different scales! For the early morning, evening and night the scale is between 0% and 7%, during the day from 09 to 17 UTC it is between 0% and 22% UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 76.5 % NA: 36.1 % Calm: 77.2 % Calm: 77.1 % Variable: 0.8 % Variable: 0.9 % UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 14.2 % NA: 8.7 % Calm: 77.7 % Calm: 76.7 % Variable: 1.0 % Variable: 1.2 %

20 Wind Aeronautical Climatological Information Lugano LSZA UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 7.1 % NA: 6.7 % Calm: 70.8 % Calm: 59.8 % Variable: 1.0 % Variable: 0.8 % UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 6.8 % NA: 7.1 % Calm: 46.7 % Calm: 34.9 % Variable: 0.6 % Variable: 0.9 %

21 Wind Aeronautical Climatological Information Lugano LSZA UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 6.7 % NA: 6.9 % Calm: 29.2 % Calm: 25.3 % Variable: 0.8 % Variable: 0.9 % UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 7.5 % NA: 7.5 % Calm: 24.5 % Calm: 25.3 % Variable: 1.2 % Variable: 1.4 %

22 Wind Aeronautical Climatological Information Lugano LSZA UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 7.1 % NA: 7.1 % Calm: 30.6 % Calm: 41.3 % Variable: 1.7 % Variable: 1.8 % UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 8.0 % NA: 13.8 % Calm: 54.8 % Calm: 66.3 % Variable: 2.4 % Variable: 2.7 %

23 Wind Aeronautical Climatological Information Lugano LSZA UTC UTC > 40 kt kt kt kt 6-10 kt 1-5 kt > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 26.9 % NA: 54.8 % Calm: 70.9 % Calm: 75.0 % Variable: 2.2 % Variable: 1.8 % UTC > 40 kt kt kt kt 6-10 kt 1-5 kt NA: 90.3 % Calm: 76.5 % Variable: 2.5 %

24 Wind Aeronautical Climatological Information Lugano LSZA Wind Speed and Direction Wind Speed and Direction 10 Years Frequencies in percent of concurrent wind direction (in 30 sectors) and wind speed within specified ranges. Calm is for the wind speed with 0 kt. Variable is for the wind speed between 1 and 3 kt. Frequencies are calculated relative to all potentially possible minus the not available (NA) observations. The value of NA is calculated relative to the potentially possible observations. It indicates the reduction of the data base due to NA. Light grey shading denotes values where the phenomena were observed. Example (dark shading): In the 10 years period 4.2% of all observations showed a wind speed between 1 and 5 knots with a concurrent wind direction between 350 and 010 degrees. Wind Speed (kt) 10 Years > 50 NA Calm Variable

25 Wind Aeronautical Climatological Information Lugano LSZA Wind Speed and Direction per Season Example (dark shading): In the 10 years period in winter 4.8% of all observations showed a wind speed between 1 and 5 knots with a concurrent wind direction between 350 and 010 degrees. Wind Speed (kt) Winter (Dec/Jan/Feb) > 50 NA Calm Variable Wind Speed (kt) Spring (Mar/Apr/May) > 50 NA Calm Variable Wind Speed (kt) Summer (Jun/Jul/Aug) > 50 NA Calm Variable Wind Speed (kt) Autumn (Sep/Oct/Nov) > 50 NA Calm Variable

26 Wind Aeronautical Climatological Information Lugano LSZA Wind Speed and Direction per Month Example (dark shading): In the 10 years period in January 5.3% of all observations showed a wind speed between 1 and 5 knots with a concurrent wind direction between 350 and 010 degrees. Wind Speed (kt) January > 50 NA Calm Variable Wind Speed (kt) February > 50 NA Calm Variable Wind Speed (kt) March > 50 NA Calm Variable Wind Speed (kt) April > 50 NA Calm Variable

27 Wind Aeronautical Climatological Information Lugano LSZA 25 Wind Speed (kt) May > 50 NA Calm Variable Wind Speed (kt) June > 50 NA Calm Variable Wind Speed (kt) July > 50 NA Calm Variable Wind Speed (kt) August > 50 NA Calm Variable